NEUTRON-ACTIVATION FOR LOGGING THE DISTRIBUTION OF GOLD IN BORE-HOLE CORES

A new method for the non-destructive determination of gold in bore-hole cores has been developed using instrumental neutron activation analysis with a Cf-252 source. The procedure obtains the distribution and concentration of gold along the longitudinal axis of the core i.e. a log of the gold concentration. The accuracy of the method is comparable to fire assay at a level of 2 ppm and has a detection limit of 1 ppm under the conditions used. The assay of the gold is carried out by employing a novel variation of the conventional comparator method using gold wires as both standard and flux monitor. A method is described for logging gold in bore-hole cores using neutron activation with a 160-mu-g Cf-252 neutron source. The method has a limit of detection of about 1 ppm under the described conditions.